Add Contributor Covenant badge

[eyllanesc]

No description provided.

[cjolowicz]

Saving the build log here for later reference. On Windows, the pip install step succeeded even though cookiecutter installation timed out.

build log

Run pip install --constraint=.github/workflows/constraints.txt pip
  pip install --constraint=.github/workflows/constraints.txt pip
  pipx install --pip-args=--constraint=.github/workflows/constraints.txt cookiecutter
  pipx install --pip-args=--constraint=.github/workflows/constraints.txt nox
  pipx inject --pip-args=--constraint=.github/workflows/constraints.txt nox nox-poetry
  pipx install --pip-args=--constraint=.github/workflows/constraints.txt poetry
  shell: C:\Program Files\PowerShell\7\pwsh.EXE -command ". '{0}'"
  env:
    pythonLocation: C:\hostedtoolcache\windows\Python\3.10.[2](https://github.com/cjolowicz/cookiecutter-hypermodern-python/runs/5282869779?check_suite_focus=true#step:4:2)\x64
Requirement already satisfied: pip in c:\hostedtoolcache\windows\python\[3](https://github.com/cjolowicz/cookiecutter-hypermodern-python/runs/5282869779?check_suite_focus=true#step:4:3).10.2\x6[4](https://github.com/cjolowicz/cookiecutter-hypermodern-python/runs/5282869779?check_suite_focus=true#step:4:4)\lib\site-packages (22.0.3)
creating virtual environment...
installing cookiecutter...
Fatal error from pip prevented installation. Full pip output in file:
    C:\Program Files (x86)\pipx\logs\cmd_2022-02-22_03.42.41_pip_errors.log

pip seemed to fail to build package:
    cookiecutter

Some possibly relevant errors from pip install:
    ERROR: Could not install packages due to an OSError: HTTPSConnectionPool(host='files.pythonhosted.org', port=443): Max retries exceeded with url: /packages/a2/62/d061b19f3074[5](https://github.com/cjolowicz/cookiecutter-hypermodern-python/runs/5282869779?check_suite_focus=true#step:4:5)550[6](https://github.com/cjolowicz/cookiecutter-hypermodern-python/runs/5282869779?check_suite_focus=true#step:4:6)e63825586e2e1816b[7](https://github.com/cjolowicz/cookiecutter-hypermodern-python/runs/5282869779?check_suite_focus=true#step:4:7)1d56b4a5[8](https://github.com/cjolowicz/cookiecutter-hypermodern-python/runs/5282869779?check_suite_focus=true#step:4:8)73c278cb315b[9](https://github.com/cjolowicz/cookiecutter-hypermodern-python/runs/5282869779?check_suite_focus=true#step:4:9)660/cookiecutter-1.7.3-py2.py3-none-any.whl (Caused by ConnectTimeoutError(<pip._vendor.urllib3.connection.HTTPSConnection object at 0x000002504EF07340>, 'Connection to files.pythonhosted.org timed out. (connect timeout=15)'))
Error installing cookiecutter.

creating virtual environment...
installing nox...
done! 
  installed package nox 2022.1.7, installed using Python 3.9.[10](https://github.com/cjolowicz/cookiecutter-hypermodern-python/runs/5282869779?check_suite_focus=true#step:4:10)
  These apps are now globally available
    - nox.exe
    - tox-to-nox.exe
installing nox-poetry...
done! 
  injected package nox-poetry into venv nox
creating virtual environment...
installing poetry...
done! 
  installed package poetry 1.1.[13](https://github.com/cjolowicz/cookiecutter-hypermodern-python/runs/5282869779?check_suite_focus=true#step:4:13), installed using Python 3.9.10
  These apps are now globally available
    - poetry.exe

[cjolowicz]

@eyllanesc I'm on the fence about adding this badge to generated projects. I was actually going to remove the Black and pre-commit badges, as well. I think that generated projects should be minimal and functional. Badges for CI and docs are great, but these "bells and whistles" badges, not so sure. I feel that the "users of our users" won't really care.

On the other hand, I feel that this badge would be great to have on the Cookiecutter repository. Users of the template do care. The badge signals to them at one glance what'll be inside generated projects.

[eyllanesc]

@cjolowicz

1. It would be good to discuss the relevance of the badges and see if the "users of our users" consider it relevant. There are several types of "users of our users": If our user creates a final application then his users will not be interested but if he creates libraries then his users will be interested as well as our users. Our users' collaborators also care.

2. I think it's great, in a few moments I'll create a PR updating the COC and add the badge.